i have a pc that needs a clean install, i have a XP HOME disc (same as current OS) but its not the same XP home disc supplied with this PC. my question is, if i do a clean install with this disc, what will happen with regards to the license key, will i need a new one or can i use the current key (sticker on the side of PC) and will this work. because in theory im not using it for a different computer???